P1311: LONG-TERM SAFETY AND EFFICACY OF EXTRACORPOREAL PHOTOPHERESIS AS EARLY SECOND-LINE TREATMENT FOR PATIENTS WITH STEROID-DEPENDENT OR REFRACTORY ACUTE GRAFT-VERSUS-HOST DISEASE.
Authors: Eleni Gavriilaki, Ioannis Batsis, Eleni Papchianou, Georgios Karavalakis, Alkistis Kyra Panteliadou, Zoi Bousiou, Despina Mallouri, Christos Demosthenous, Aikaterini Soulani, Asimina Bouinta, Anna Vardi, Evangelia Yannaki, Nikolaos Spyridis, Damianos Sotiropoulos, Achilles Anagnostopoulos, Ioanna Sakellari
Journal: HemaSphere (2023)

Topic: 22. Stem cell transplantation - Clinical Background: Despite novel biologic agents, steroid-dependent or -refractory acute graft-versus-host disease (aGVHD) remains a severe complication of allogeneic hematopoietic cell transplantation (alloHCT). Aims: Based on our long-lasting experience with extracorporeal photopheresis (ECP), we aimed to prospectively assess the role of ECP as early second-line treatment in steroid-dependent and refractory aGVHD. Methods: We enrolled consecutive patients with steroid-dependent or refractory grade (gr) II-IV aGVHD post alloHCT over the last decade (January 2013 - December 2022). All patients with unrelated or haploidentical donors received thymoglobulin (ATG) 5mg/kg as prophylaxis. Post-transplant GVHD prophylaxis included cyclosporine – methotrexate in myeloablative and cyclosporine – mycophenolate mofetil in reduced toxicity or intensity regimens. ECP was commenced after assessment of response to 5 days of steroid treatment according to our protocol: 2 sessions/week for 1 month, 1 session/2 weeks for 3 months, evaluation of response and 1 session/month for 6 months. Before ruxolitinib’s availability, ATG was commenced simultaneously with ECP initiation in steroid-refractory patients. Results: We studied 28 patients, aged 45 (18-67), post alloHCT with myeloablative (16), reduced toxicity (8) and intensity (4) conditioning, from sibling (4), matched (11) or one locus mismatched (12) volunteer unrelated and haploidentical (1) donors. Disease risk index was very high (1), high (11), intermediate (14) and low (2). Acute GVHD was observed at day +17 (8-50). Skin, intestine and liver involvement was evident in 9 patients, skin and intestine in 13 and skin only in 6 patients. Thirteen patients were steroid-dependent and 15 steroid-refractory. ECP was commenced at day +18 (8-56) for 15 (4-20) sessions. The majority of patients (19/27) presented partial (7), very good (11) or complete (1) response to ECP. With 9.9 (1.7-113) months of follow-up, immunosuppression was reduced in 12/27 and ceased in 1 patient. Clinically significant bacterial infections were found in 19 patients, fungal in 3, CMV and EBV reactivation in 19 and 12 respectively and other viral in 6 patients. Cumulative incidence (CI) of chronic GVHD was 56.4 at 1-year.Five-year overall survival (OS) was 34%. Reduction of immunosuppression (p=0.026) and number of ECP sessions (p<0.001) were associated with improved OS, irrespectively of other factors. In particular, optimal OS was observed in patients that received more than 19 ECP sessions (Figure). Summary/Conclusion: Our data confirm that ECP should be considered early in the course of steroid-dependent or refractory aGVHD, even in the era of novel biologic agents. Optimal timing of intervention, frequency, duration and tapering schedule of ECP remain important unanswered questions.Keywords: Allogeneic, Graft-versus-host disease (GVHD), Hematopoietic cell transplantation, Extracorporeal photopheresis